To test a psychopharmacological intervention strategy which may provide new insights into the mechanisms underlying the physiological hyperreactivity to stress observed in hypertension, we plan to test the effects of the neuropeptide oxytocin and social support on the neurobiological and psychological responsiveness to social stress. The study population for this project consists of 80 hypertensive and 80 normotensive non-smoking medication-free men. We expect exogenous oxytocin administration to enable hypertensives to effectively take advantage of the provided social support. Thereby, oxytocin may enhance the effect of social support on reducing the previously observed physiological hyperreactivity to stress in essential hypertensives.